Unusual ceiling light wiring

[joeninho]

Hi guys,

So far, I have managed to install 4 of my 6 ceiling lights with some research and great forum advice. I should point out at this stage that I do my homework and I would not be installing anything that I was not 100% sure about.

In the 5th light fitting, I have come across an unusual (to me!) scenario from the two cables coming from the ceiling.

The two black wires are both connected to the brown lives on the light fitting and the two red cores are connected to the two (blue) neutral wires. This is a situation I have not come across before. The two earth wires are loose, I assume as there is no earth on the old ceiling light fitting. I will sleeve these and attach them to the earth on the new fitting.

With the previous fittings, I am used to having one black as the switched live connected to the live in the new light, and the other as a neutral connecting to the new neutral, with both reds being terminated in a separate block.

Can anyone offer me some advice on how to proceed?

I have a multimeter if it is required to test any of the wires.

Photograph attached.

Many thanks,

Joe.

 

[Ragnar_AT]

Does the current light work? How many lights are there in the room?
I can see two likely scenarios. Either someone connected the light wrong or the wires in the ceiling are connected the wrong way round somewhere. Use the multimeter on Volts AC and measure from red and black to earth while the light is on. If you get 230-ish V on the red and close to zero on the black just connect the new light correctly.

 

[Taylortwocities]

It looks to me that some numpty has just connected up the light the wrong way round.
On the new light simply connect the L to the red and N to the blacks. SLEEVE the earth wires and connect to the light's earth terminal.

 

[joeninho]

Firstly, thanks for the prompt replies. Much appreciated!

The light is on a hallway with several other lights, and yes, the light currently works.

Do I need to consider one of the blacks being a switched live and terminating the two reds? Or simply connect red to brown, blue to black and the earths to the new fitting?

Thanks again,

Joe.

 

[Ragnar_AT]

If the light works you‘ve got a switched live and a neutral coming in and obe of each going to the next light. Perfectly fine. All you need to do is measure whether red is actually the switch line, and if it is, connect the new light as you suggested. If you find the colours are the wrong way round you should try to fix that.

 

[joeninho]

I have now tested the wires using a multimeter.

I disconnected the old fitting, switched the power off and separated the wires to allow for safe testing. Switched the power back on and tested all wires.

Tested between both blacks and earth and both reds and earth.

All of the readings were 0 apart from one of the reds, which was showing 80 volts.

Can I now proceed with connecting both blacks to neutral and both reds to live on the new fitting?

Thanks again,

Joe.

 

[Taylortwocities]

All of the readings were 0 apart from one of the reds, which was showing 80 volts.

With the power on you should get 230volts between the reds and the blacks. Do you?
If you are testing to earth, if you are only getting 80volts on the reds, that seems to indicate that the earth wires arent connected to earth somewhere!
Neutral is esentially at zero volts, so you wouldn.t expect to get a reading there if testing to earth..
PS, for testing, do not separate the earths. The earth may be coming from an unknown direction!


Re this bit:

I have managed to install 4 of my 6 ceiling lights

What i think we are looking at is a red (switched live) and a black (neutral) from one of the other lights and the other red and black is switched feed out to the next light.

 

[joeninho]

Sorry, absolute numpty error by me. I didn't have the light switch on!

Now measuring 240v between one red and black. Also reading 240v between earth and that red.

No reading from the other red/black.

 

[Taylortwocities]

Sorry, absolute numpty error by me. I didn't have the light switch on!

Doh!

Now measuring 240v between one red and black. Also reading 240v between earth and that red.

Great, so the earth is there

No reading from the other red/black.

Yes, probably that cable goes to another one of your lights

Can I now proceed with connecting both blacks to neutral and both reds to live on the new fitting?

Yes! plus the (sleeved) earth

 

[joeninho]

Awesome, Taylor.

Thank you!

 

[joeninho]

Thanks again for you help, guys. Hugely appreciated.

That's number 5 installed.

Just need to figure out how to get high enough to change the fitting above the stairs now!